This application claims the priority of Austrian Patent Application Ser. No. GM 512/2000, filed Jul. 13, 2000, the subject matter of which is incorporated herein by reference.
The present invention relates, in general, to a track renewal machine.
U.S. Pat. No. 4,854,243 describes a machine for renewing a track composed of two rails fastened to ties supported on ballast. The track renewal machine includes a machine frame extending in a longitudinal direction and having opposite ends supported on the track by undercarriages. The machine frame has a front frame part and a rear frame part, arranged one following the other in the longitudinal direction, with a frame joint connecting the front and rear frame parts to one another. Drives interconnect the front and rear frame parts in an upper region thereof to spread the frame parts apart, whereby the frame parts are raised in a vertical direction at the frame joint. The machine further includes a tie lifting device and a tie laying device, mounted on the machine frame between the undercarriages and spaced from one another in the longitudinal direction; an endless ballast clearing device for taking up ballast, mounted on the machine frame between the tie lifting device and the tie laying device and designed to be set in rotation by a drive; and first conveyor, cooperating with the ballast clearing device, for transporting away taken-up ballast. After removal of the old ties, ballast from the cribs between the ties remains lying on the ballast bed, creating an obstacle for laying the new ties. This crib ballast is taken up by the ballast clearing device, having the shape of an endless chain, and is transported upwards to the conveyor. After being moved to the rear end of the machine, the ballast is discharged upon the new track which has been laid in the meantime in the intervening space. This serves to ballast the new ties resting on the newly graded ballast bed and thus to stabilize the track position.
French Pat. No. FR 2 736 367 A describes a track renewal machine which essentially includes a first machine unit for picking up the old ties, a trailing ballast cleaning unit, and a further machine unit for laying the new ties. The ballast cleaning unit includes a clearing chain which cooperates with a ballast screen in which the soiled ballast is cleaned. Located immediately behind the clearing chain in the operating direction is a ballast discharge station for returning cleaned ballast to the track, and a planing and consolidating device.
It would be desirable and advantageous to provide an improved track renewal machine which is optimally suited for track renewal work and yet can be simultaneously also employed for cleaning an exposed or excavated ballast bed.
According to one aspect of the present invention, a machine for renewing a track composed of two rails fastened to ties supported on ballast, includes a machine frame extending in a longitudinal direction and having opposite ends supported on the track by undercarriages, wherein the machine frame includes a front frame part and a rear frame part, arranged one following the other in the longitudinal direction, a frame joint connecting the front and rear frame parts to one another, and a drive interconnecting the front and rear frame parts in an upper region thereof and effective to spread the frame parts apart, wherein the frame parts are raised in a vertical direction at the frame joint; a tie lifting device and a tie laying device, mounted on the machine frame between the undercarriages and spaced from one another in the longitudinal direction; a rotatable endless ballast clearing device, mounted on the machine frame between the tie lifting device and the tie laying device, for taking up ballast; a first conveyor, cooperating with the ballast clearing device, for transporting away taken-up ballast; a second conveyor for transporting ballast, said second conveyor extending in the longitudinal direction and having a discharge end arranged between the ballast clearing device and the tie laying device; a ballast discharge device associated with the discharge end of the second conveyor; and a ballast planing device arranged between the ballast clearing device and the tie laying device and including a drive for vertically adjusting the ballast planing device.
Through the provision of a track renewal machine according to the present invention with two-part machine frame of articulated design which is supported at opposite ends on the track by undercarriages, it is now possible in a particularly advantageous manner to exploit the renewal gap, which is easily accessible as a consequence of a temporary removal of the track, for taking up ballast in a simplified and problem-free way. Since there is no track present in the renewal gap to create an obstacle, it now is very easy to clean even especially problematic areas, such as platforms, for example, where, in the course of normal cleaning operations with lifting of the track, there would normally not be sufficient space for operating a clearing chain.
An added advantage can be found in the possibility to precisely control or guide the vertical position of the clearing chain or the ballast planing device by tracing the vertical position of the immediately preceding old ties before the removal thereof, in order to accurately re-establish the track position. Thus, the pre-existing vertical position of the old track can be precisely reproduced by the new track. When the ballast clearing chain is moved to its idle position on the machine frame, the track renewal machine can be employed without any restrictions for regular track renewal operations, without involving cleaning of the ballast bed. As the track renewal machine is supported on undercarriages only at the opposite ends of the machine frame, it is possible to easily produce an exactly planed and consolidated ballast formation for the new track position.